What are the scrolling limits of a Virtual Tree View?

How can I get the max scroll for the X an开发者_运维问答d Y in virtualstringtree during onchange event?

The GetTreeRect method gives the dimensions in pixels of the entire tree, or the dimensions of the client area, whichever is larger. Note that if there are no columns configured, then the size of the tree can vary based on which nodes are displayed on the screen at the time — the scrolling width changes according to the widest nodes visible.

The Bottom and Right fields of that rectangle determine the scroll-bar range.